London demolish and rebuild project at 2 Aldermanbury Square sees hundreds of tonnes of steel frame reused

 

 

2 Aldermanbury Square
2 Aldermanbury Square is a prime example of how steel can be reused in construction

Thousands of outdated high-rise office blocks are taking up space in cities worldwide. Updating or replacing them sustainably is a challenge, one that 2 Aldermanbury Square in the City of London successfully took on.

British property company Great Portland Estates was keen to turn its obsolete, 1980s-built, ten-storey City Place House in the City of London into a sustainable office building suited to the demands of twenty-first-century working practices. Refurbishing the property was considered, but following a detailed life cycle analysis, this was found to be more carbon-intensive than redeveloping the site.

Architects Allies and Morrison were tasked with doing just that and what has been built is one of the most environmentally progressive new buildings in the City of London. Opportunities to improve the sustainability of the building’s design and operations were taken right from the planning stage through to completion and operation. This made it possible to reduce the project’s embodied carbon by 36% from the initial design. How steel was used in the design and build was a big contributor to this.

The new 13-storey, 322,600 sq ft building, which is now called 2 Aldermanbury Square, has been constructed reusing around 80 tonnes of steel from the original City Place House structure. This has been used for roof plant areas and trimmer steels. The rest of the 1,800 tonnes of steel left over from the demolition is set to be reused on another central London development.

2 Aldermanbury Square, City of London
2 Aldermanbury Square gives new life to old steel

The steel reuse required precision engineering

Construction engineers Keltbray worked out a way to remove the steelwork from the original building at maximum length without damage. This meant that 90% of the steel from the original development could be reclaimed and reused, rather than recycled, which aligns better with circular economy principles and greatly lowers embodied carbon.

Meanwhile, the new steel that was used was sourced from electric arc furnaces powered by renewable energy and all construction work was powered with alternative fossil-free fuels and renewable electricity.

Due for completion in 2026 and pre-let to law firm Clifford Chance, the new development is on track to  achieve an Energy Performance Certificate rating of ‘A’, BREEAM ‘Outstanding’, NABERS 5* Design for Performance and to be WELL Core Gold ‘Enabled.’

If these steel-reuse construction methods become mainstream, then steel could soon have multiple lives in buildings across the world.